Schedule Project Actual: Duration, Forecasts, and Network Diagrams
PMBOK v8 Definition
Schedule forecasts are estimates or predictions of conditions and events in the project's future based on information and knowledge available at the time the schedule is calculated. The schedule forecast predicts a timeline based on current progress, performance trends, and other information pertaining to the project. Forecasts are updated and reissued based on work performance information provided as the project is executed.
Actual duration is the time, in calendar units, between the actual start date of the schedule activity and the data date of the project schedule, if the schedule activity is in progress, or the actual finish date if the schedule activity is complete.
Project schedule network diagrams are graphical representations of the logical relationships (also called dependencies) among the project schedule activities.
Note: These concepts are part of the Schedule Management Knowledge Area, specifically within the Develop Schedule and Control Schedule processes.
Why It Matters for the Exam
The PMI exam frequently tests your understanding of how actual performance data drives schedule forecasts and updates. Questions appear in both situational (scenario-based) and definitional formats, often asking you to distinguish between actual duration, planned duration, and remaining duration. Expect 2-4 questions linking schedule forecasts to earned value management (EVM) and corrective actions.
Key Points to Remember (for the exam)
- Schedule Forecast Definition: Based on information available at the time the schedule is calculated, not on initial plans or assumptions
- Forecast Update Trigger: Work performance information obtained as the project is executed
- Actual Duration Formula: Time from actual start date to data date (if in progress) OR to actual finish date (if complete)
- Data Date Critical: The reference point for all schedule calculations and forecasts
- Two Forecast Components: Past performance + expected future performance based on corrective or preventive actions
- Network Diagram Purpose: Shows logical relationships (dependencies) among schedule activities
- Common Confusion: Actual duration is NOT the same as planned duration—actual duration uses real start/finish dates, not planned dates
Typical PMI Exam Example
A project is 60% complete. Activity A started on March 1 and is still in progress. The data date is April 15. What is the actual duration of Activity A?
Answer: The time from March 1 to April 15 (data date) = 45 calendar days. Actual duration uses the data date for in-progress activities, not the planned finish date.
PMI Exam Traps
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Trap: Confusing actual duration with remaining duration
Reality: Actual duration measures time already spent; remaining duration estimates future time needed -
Trap: Assuming schedule forecasts are static once created
Reality: Forecasts are updated and reissued based on ongoing work performance -
Trap: Thinking actual duration uses planned start dates
Reality: Actual duration uses the actual start date, which may differ from the planned start date -
Trap: Confusing schedule forecasts with cost forecasts
Reality: Schedule forecasts predict timeline; cost forecasts predict budget performance
Important PMI Connections
| Related Concept | Relationship Type | Exam Attention Point |
|---|---|---|
| Schedule Management Plan | Input to Develop Schedule | Specifies scheduling methodology and tool for developing the schedule model |
| Work Performance Information | Input to Schedule Forecasts | Drives forecast updates—tested on what triggers re-forecasting |
| Variance Analysis | Complementary Technique | Schedule forecasts use variance trends to predict future performance |
| Corrective/Preventive Actions | Output of Control Schedule | Forecasts incorporate expected impact of actions taken |
| Data Date | Foundation Element | All schedule calculations reference this single point in time |
Quick Review Questions
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What is the difference between actual duration for a completed activity versus an in-progress activity?
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When are schedule forecasts updated and reissued during the project lifecycle?
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What two types of information form the basis of schedule forecasts?
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Why is the data date critical for calculating actual duration?
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How do corrective actions affect schedule forecasts according to PMBOK v8?
PMBOK v8 Reference
Section 2.3 - Schedule Management (derived from the provided context on schedule forecasts, actual duration, and project schedule network diagrams)
Note: The specific section numbering may vary by PMBOK v8 edition; the concepts are consistently located within the Schedule Management Knowledge Area, primarily in the Develop Schedule and Control Schedule processes.